1. Field of the Invention
The present invention relates to an electronic system having an electronic apparatus such as portable computer, and a cooling apparatus to be used by coupling with the electronic apparatus.
2. Discussion of the Related Art
The power consumption of a portable electronic apparatus, such as a notebook computer, has been increasing due to higher processing speeds and multi-functionality of the microprocessor, and the microprocessor heat value tends to increase rapidly in proportion. Therefore, it is necessary to improve the heat radiation from the microprocessor in order to secure stable operation of portable computers.
As a countermeasure thereof, a conventional portable computer contains a heat sink thermally connected to the microprocessor, and there is an electric fan to provide cooling air to the heat sink, which cools down a hot microprocessor.
According to this conventional cooling method, as the cooling air supplied from the electric fan becomes a cooling medium for absorbing the heat from the microprocessor, the microprocessor cooling capacity depends largely on the blowing capacity of the electric fan. As a result, if the flow of cooling air is increased to enhance the microprocessor cooling capacity, the electric fan typically increases in size. Consequently, a large space would be required inside the housing of a portable computer for installing a bulky electric fan.
In general, for a portable computer, the housing is designed to be thin and compact because portability is a critical element for enhancing its product value. Therefore, a space for containing a large electric fan of a large blowing capacity or a draft air path for cooling air is too large be secured in the housing. As a result, there may be a concern that in the conventional cooling method, the microprocessor cooling capacity may be insufficient or may reach the thermal limit.
On the other hand, it is difficult to secure an installation section of connectors for connecting, for example, input/output devices and a space for containing a CD-ROM drive unit, due to the thinning of the housing, for portable computers. Therefore, recent portable computers are provided with an expansion connector and can obtain an expansion ability comparable to that of desktop computers, by connecting this expansion connector to an expansion apparatus called a docking station.
The conventional expansion apparatus typically includes a box-shape apparatus main body with built-in apparatuses for function expansion, such as a CD-ROM drive unit, a DVD drive unit, or the like. The apparatus main body has a top face on which the housing of the portable computer is placed, and a relay connector is arranged on this top face. The relay connector fits into the aforementioned expansion connector when the housing is put on the top face. A mutual fitting of these connectors allows an electric conduction of signal path for various control signals, such as mutual logical address, or a data path of the portable computer and the expansion apparatuses.
Among such kinds of expansion apparatuses, one for installing a heat sink in the apparatus main body and for cooling a heat sink with air blown by an electric fan is known. According to this expansion apparatus, when the housing of the portable computer is placed on the apparatus main body, this housing comes into contact with the heat sink. Consequently, heat conducted from the microprocessor to the housing is dissipated by heat conduction to the heat sink and borne by the flow of cooling air radiated outside the housing. Therefore, the portable computer may be cooled by using the expansion apparatus, thereby enhancing the cooling function of the portable computer.
However, an extremely thin and light notebook-type portable computer is designed to be mobile, and adapted to receive/transmit data from/to a client, or for use in a presentation at the premises of a client. Therefore, in the conventional configuration for supporting the microprocessor cooling by means of an expansion apparatus, it is necessary to carry all of the times a heavy and bulky expansion apparatus together with the portable computer. Consequently, it becomes impossible to put the portable computer in a bag, or the like, and carry about it easily, thus sacrificing its inherent portability.
In the case of just carrying solely the portable computer, the microprocessor cooling capacity may be insufficient. Therefore, especially when the microprocessor is tasked to execute complicated calculations and processing, there is a fear that the temperature of the microprocessor may exceed the operational limits. If the temperature of the microprocessor becomes too high, the processing speed may become slower, or the operation may become impossible due to thermal overload. Consequently, it becomes impossible to completely utilize all of the performance features of the microprocessor.